In the diagnostics field, there are a large number of important analytes relating to human disease condition, genetic makeup or gene activity, environmental factors and biowarfare agents. In many cases, these analytes can only be detected, in a practical sense, by multi-step processing in solution. For example, when assaying a particular cell or tissue mRNA transcript, various processing steps, such as cell lysis, isolation of mRNA transcripts, selective amplification of known-sequence transcripts and detection may be required, each requiring a separate liquid-phase reaction or processing step.
Heretofore, the most widely used and available approaches for carrying out multi-reaction assays and reagent manipulations of thus type have been fairly user intensive, requiring a user to set up different reagent vessels, transfer solutions or suspensions from one vessel to another, agitate some vessels during washing steps, and keep track of reaction times required in each vessel. The time and cost of these procedures is one limitation of their use. In addition, the sample amounts needed in these types of assays can be significant. Most restrictive, perhaps, is the problem that these procedures are impractical or impossible in many point-of-care (POC) settings, such as small clinics, screening centers, or battlefield settings.
Although automated microfluidics devices for carrying out multi-step liquid-phase reactions have been developed, and in some cases, commercialized, these systems tend to be fairly expensive, require special control and detection instruments, and have limited adaptability in terms of user-directed changes in reagents and analytes to be detected or reagents to be manipulated.
For these reasons, there exists a continued need for a low cost, reliable, automated, flexible apparatus for chemical handling and processing, especially in the diagnostic and pathogen detection areas, and especially for POC applications.